Communicating with LED based lighting fixtures involves varying the current that flows through the LED light sources of the lighting fixtures based on the information being sent. Varying of the current to reflect the information being sent results in changes in the intensity of light emitted by the LED light sources. To avoid detection of the change in the emitted light by occupants, the varying of the current needs to be performed at a fast enough rate. However, most constant current drivers (e.g., switching regulators) are unable to quickly change their current output because of a slow control loop. While a slow control loop may be desirable during an operation of a light fixture to illuminate an area (e.g., to avoid flicker), slow change in current is undesirable during visible light communication due to the likelihood of detection of the change by occupants.
Thus, a driver that allows relatively fast current changes during visible light communication and relatively slow current changes during illumination by LED light sources is desirable.